Pneumatic conveyer tube joint



Aug. 15, 1950 E. J. STOECKLIN PNEUMATIC CONVEYER TUBE JOINT Filed Feb. 6, 1948 INVENTOR.

Arrow/v5 Patented Aug. 15, 1950 UNITED STATES PA. 1. f: NT OFFICE amazes PNEUMATIC converse. TUBE JOINT Edward J. Stceckiin, Cincinnati, Ohio.

Application February 6, 1948, Serial No. 6,737

Claims.

This invention relates to pneumatic tube systems of the type used to convey or dispatch papers and other articles by air pressure or vacuum from a dispatching to a receiving station.

' made up individual tag; ends joinedtogether to form a continuous airtight conveyor tube extending between the stations.

The present invention is directed in particular to an improved connector to provide an airtight joint and" permit relative Or full floating movement of the tube sections by reason of contraction and expansion. While intended primarily for pneumatic tube systems, the connectoralso is adapted for similar applications, particularly where contraction and expansion due to tempera ture changes is encountered,

Expansion and contraction of the tubing is an important problem in outdoor dispatch systems and the present structure has been developed primarily to solve this difficulty. As disclosed, the system is installed ina railway yard to exemplify a typical application of the principles involved. It will be apparent that it may be applied with equal facility to other outdoor uses such as a conduit between separated buildings such as ofiice and factory buildings and to industrial uses generally to convey messages, papers and the like between various points.

As applied to railway usage the system serves to dispatch waybills and other papers between a central ofiice building and remote parts of the yard. The system may be a mile or more in length, and permits rapid transmission of papers to and from the'trainmen as freight trains are I? made up, usually a considerable distance from the office. Thus waybills and other papers used in the record system and bearing information relative to each car, may be sent rapidly to or from the scene of operations and the office. The papers are placed in carrier units, which are inserted in the tube system and propelled rapidly by air pressure or vacuum to their destination.

When installed out of doors the system is exposed to temperature variations of considerable magnitude. By way of example the temperature of the tube may reach 100 F. or higher in summer and may drop to 0 F. or lower during the winter season. If the ends of the tube sections are rigidly joined together a noticeable changein length occurs due to expansion. This presents a problem which becomes more troublesome as If there is an angular section such as a rise or fall, the" the length of the system increases.

length increase tends to accumulate at this point -of time this tends to stressing and tending to rupture the tube, and if the tube is straight it tends to buckle. The difference between day and night temperatures also causes daily contraction and expansion which tends to fatigue the metal even though the degree of expansion is considerably less than that due to seasonal temperagire changes.

The sections from which the system is constructed preferably consist of a commercial grade of tubing, formed of aluminum or similar corrosion resistant metal which has a relatively high coefficient of expansion. Also to reduce costs such tubing has fairly high limits of tolerance which makes more difficult the establishment of an airtight joint between. the sections.

A primary object of the inventor therefore has been to provide an expansion joint or connector for such tubes which compensates for tolerance s'in size and contour to provide an airtight joint and which permits the adjoining ends of the tubes freely to shift longitudinally due to contraction and expansion without loss of air pressure, thereby making each tube section in- 'dividually 'expansible and eliminating expansion problems regardless of the length of the system.

The system usually is installed above ground, being supported by posts at spaced intervals to provide a continuous conduit. Additional problems encountered in a system of this kind, include the difficulty of maintaining the tube 1n tube is made up of a straight line. When the sections rigidly secured together and rigidly secured to these posts, the posts are stressed due to expansion and contraction and over a period disturb, the alignment of the posts and tube, leading to potential failures in the system. An important feature of the present structure is the manner in which each tube section is mounted loosely at its center leaving its opposite ends slidably supported by the expansion joint so that there is no stressing of the posts. In other words each individual tube section floats relative to its adjacent sections and posts, consequently there is no accumulation "of expansion lineally which normally would tend to displace the posts and case tube damage.

Another object of the inventor, therefore, has been to provide an improved mounting arrangement which makes each of the tube sections independently expansible whereby stressing and dispiaeement of the system posts are eln 'i" alignment oi the tube is mag-m accurately. g ther object of the prese t inventor has been to provide a continuous conduit system,

made up of tube sections as above set forth, which includes mounting and coupling means for maintaining the system in proper alignment and which does not permit the transmission of noise because of the sound insulating means included in the connections.

Further objects and advantages of the invention Will be more fully disclosed in the detailed description with reference to the accompanying drawings in which:

Figre l is a general diagrammatic perspective view illustrating a pneumatic tube system employing the improved expansion joint and mounting arrangement.

Figure 2 is an enlarged fragmentary side elevation, illustrating a portion of the tube system with the improved expansion joint assembly secured to and supporting the ends of the tubes relative to a mounting post.

Figure 3 is a fragmentary View in cross section illustrating the structural details oftheexpansion joint .in assembled relationship with. the.

ends of the tubes.

Figure 4 is a cross section taken on line 44,

Figure 3, further illustrating the joint structure,

its mounting bracket and manner of attachment to a post Referring to Figure 1, the dispatching system is illustrated generally as applied to a railway freight yard or similar use. One'terminal ofthe system, indicated at l0,.-is connected by means of the conduit or tube -H to a. central building such as an ofiice building indicated at l2. These buildings may be located at considerable distances apart, for example in the instance of a railway yard, the central office building may be located a mile or more fromthe yard-ofiice which the system serves. The installation shown in Figure 1 is purely diagrammatic and is not intended to represent actual distances between the several points, the stations being shown relatively close together for convenience of illustration. Also the system may extend to several yard stations or offices as required by particular service conditions.

In pneumatic dispatch systems of this nature, the paper or article to be dispatched is placed within a carrier unit which fits snugly within the tube and airpressure or vacuum propels the carrier rapidly to its destination. The air pressure or vacuum may be in the neighborhood of three pounds per square inch depending. on operating conditions, and sirice the tubes are made up of sections the ends of the sections must be joined together in an airtight manner. Special devices are installed at the dispatching and receiving ends of the systemto admit the carrier unit and to deliver the unit at its dest nation without undue lossof air pressure. The structural details of the carrier unit, air pressuresupply apparatus and entry and exit devices for the carriers forms no part of the present invention, therefore these structures are not disclosed.

As previously noted, the tube system is made up of individual tube sections which may be, for example, thirty feet in length, indicated at I3 in Figure l. The adjoining ends of the sections are connected together to provide airtight joints by means of the improved connector or expansion joint indicated at I 4. The connectors are supported above ground upon a series of posts l5 preferably of wood which are set in the ground in the usual manner. If desired, the lower ends of the posts may be embedded in concrete. In the present instance these posts are set at fi ll neighborhood of of an inch to insure maximum foot centers and upon alternate posts are mounted the connector units M. The intermediate post, indicated at IS in Figure 1, serves as a support and is not provided with an expansion joint. Secured to each of the posts it is a. hanger ll engaging tube section l3 intermediate its length. The tube section I3 is carried slidably by post l6 and is free to expand in opposite directions and its opposite ends are confined slidably within .7 the connectors l4. Therefore each tube section tion and are formed from rubber or a plastic or synthetic material such as neoprene. The sleeve I 8 is secured to post i5 by means of a split bracket 20' secured to the post by means of lag screws Zl-Zl. With reference to Figure 3, it will be noted that sleeve I 8 includes a necked portion forming a throat 22 of reduced diameter, centrally of its length. The endwise portions 23 of the sleeve are sufficiently large to receive telescopically the ends of tube section Band to provide space for the sealing gaskets l9 between the tube and end portion 23. In the present disclosure, as viewed in Figure 4, the tube l3 and sleeve 18 are oval in cross section although the same structure may be applied to tubes having round or other cross sections.

It will be noted in Figure 3 that a clearance space 25 is providedbetween the flared end 26 of the tube l3 and the flared connecting portion 2'! between the throat- 22 and the enlarged end portions 23-43. The clearance may be in the expansion without the danger of jamming the end of tube l3 against the flared portion 21 under extremes in temperature ranges. In the course of experiment with aluminum tube sections under extreme temperature ranges it has been found that this amount of clearance is more than sufiicient to accommodate maximum lineal expansion with a substantial safety margin.

In orderto permit shifting of the end of the tube relative to the connector with minimum resistance, it has been found that the use of the gasket ring IQ of circular cross section is most advantageous. These sealing rings normally are somewhat greater in diameter in cross section than the space 28 between the tube and connector. Thus, there is a slight degreeof flattening which develops sealing pressure and forms substantially a line seal. When the tube section expands or contracts the gaskets l9 rcll and change their position due to the creeping of the end of the tube'relative to the connector.

In order to prevent deterioration of these yieldable sealing rings, a weather seal 29 is provided. This seal preferably takes the form of a flat strip of pliabl material and may be of the same material as the sealing rings l3. Strip 29 is clamped between a flange 30 formed at opposite ends of connector I8 and a clamping ring 3!, the clamping ring being secured to flange 30 by means of screws 32 extending through the assembly and preferably secured by nuts 33. The loose edge of strip 29 contacts and establishes a Weather seal with tube l3 and prevents the entry of dirt and moisture into the area occupied by the sealing'rings and consequently improves performance and lengthens the life period of the sealing rings. By virtue of its accessibility the weatherseal 29 mayreadily be replaced when it becomes badly worn or deteriorated by the weather. V

' The connector preferably is in the form of an aluminum casting although other methods of fabrication may be employed. It has been found however that cast connectors are somewhat cheaper and more rigid and substantial than those formed of rolled sheet metal and may be held more readily'within specified limits of contour and dimension. The interior of the connector may be smoothed somewhat by sand blasting if desired but it is not necessary to machine finish the surface in order to establish an airtight seal. It is believed that by virtue of the narrow line contact established by the sealing ring 29 under compression, the yieldability of the ring causes it to conform to and embrace closely the slight irregularities of the metal surfaces to establish the seal. It has been determined that the seal is capable of withstanding air pressure many times greater than the service pressure, without leakage.

As previously noted, the connector I8 is slidably carried by its post I5 while the ends of the tube sections are free to sliplongitudinally relative to the connector. The connector is secured by means of the split hanger bracket 20 which engages the connector in its throat portion 22. liangerzt is comprised of two identical loopshaped pieces 35-35 each having outwardly extending ears 35-36. As illustrated in Figure 4, one of the ears of each member 35 includes an angular foot 31. In the present disclosure the left hand member has a foot 31 at the top and the right hand member has a foot at the bottom, both elements 35 being identical. This arrangement spaces the loop-shaped pieces 35 relative to the throat 22 to prevent undue clamping pres sure from being applied to the connector. The loop members 35 are secured together in clamping engagement and mounted upon the post l5 by means of nuts 38 in screwthreaded engagement upon the elongated shank of screw 2!. The bracket loops 35 preferably are stiffened by flanges or beads 4l-4l formed along opposite edges as shown in Figure 2.

The nuts 323 permit the connector to be accurately adjusted toward or from the post l5. By virtue of this arrangement the posts need not be as accurately located to align the tube system as normally would be required. In order to facilitate attachment of the hanger brackets upon the screws it, the ends of the brackets are slotted as at M] (Figure 2). Slots 4!] permit the position of the connector to be adjusted vertically. Thus the tube line conveniently may be adjusted vertically and horizontally relative to the posts at the time of installation to establish alignment.

By virtue of the throat portion 22 which has a slightly greater outside diameter than the tube section it, the same hanger loop brackets 35 may be used for supporting the center of the tube section on post it as shown in Figure 1. The brackets are secured to posts IS in the same manner as disclosed with reference to the connector but being slightly larger than the tube, do not bind the tube. The throat portion 22 establishes a uniform inside diameter between the adjoining ends of the tube sections [3 as shown in Figure 3. This is of importance due to the velocity at which the carrier units pass through the tube system. It has been found in practice that any substantial obstruction or variation in diam eter tends to damage the carrier and sometimes results in breakage of the carrier unit and loss of papers carried in it. By virtue of the flared end 26 of tube It and the flared section 21 of the connector, abrupt changes in diameter are eliminated and a more gradual, non-interfering juncture line is established.

From the foregoing it will be apparent that the" connector and expansion joint structure greatly improves the performance of the tube system. By permitting unrestrained lineal expansion, breakdowns caused by stresses and fractures are substantially eliminated and by the adjustable mounting of the individual tube sections, the alignment of the sections relative to each other can be held within very close limits. This improves performance and by virtue of adjustability reduces installation and maintenance costs since the posts need not be set as accurately as otherwise required. The clearance provided by the connectors between the tube sections further expedites installation since lineal variations do not affect the overall length of the system and any variations are taken up locally by the end clearance provided by the connectors.

Having described my invention, I claim:

l. An expansible joint for dispatch tubes comprising; a connector sleeve arranged to receive telescopically the ends of the adjoining tubes, said connector sleeve having a restricted central portion substantially of the same diameter as said tubes and having endwise portions larger in diameter than said tubes to provide annular spaces, and resilient sealing rings normally of circular cross section disposed in compression in said annular spaces to establish rolling seals between the tubes and said connector sleeve.

2. A joint for tube systemscomprising; a connector sleeve, a tube section having an end disposed within said connector sleeve, a gasket formed of resilient material having substantially a circular cross section disposed between the end portion of said tube and said connector sleeve, said gasket being under compression radially to provide a seal between the tube section and connector sleeve and being substantially unconfined in a coaxial direction relative to said connector sleeve to provide a rolling seal having relatively unrestricted axial movement between the tube section and connector sleeve.

3. An expansion joint for pneumatic tube systems comprising; a connector sleeve, tube sections having their ends telescopically disposed within opposite ends of said connector sleeve, the connector sleeve being arranged to provide uninterrupted annular spaces surrounding the ends of the tube sections, respective sealing rings in said annular spaces formed from resilient material substantially circular in cross section, the sealing rings being under compression radially in said annular spaces and being free to roll longitudinally upon relative longitudinal shifting between the tubes and sleeve, and weather seals constituting flat flexible strips secured to the opposite ends of the connector sleeve and having unsupported marginal edges yieldably engaged aginst the tube sections, said resilient rings providing a rolling pressure seal and the weather seals providing a yieldable skirt movable with the tube sections to enclose and protect the rolling seals.

4. An expansible joint for pneumatic dispatch systems employing a plurality of tubular sections comprising, "a connector sleeve adapted to receive the ends of adjoining tube sections, said connector sleeve having a central throat portion substantially of the same inside dimension as said tube sections and having enlarged endwise portions adapted to receive telescopically the end portions of said tube sections, a plurality of sealing rings formed of resilient material and disposed under compression between the telescopingportions of said tube sections and the enlarged endwise portions of the sleeve to seal the tube sections relative to the sleeve, the sealing rings being normally circular in cross section to provide'rolling seals in line contact with said sleeve and tube sections adapting the tube sections' to shift axially relative to the connector sleeve, and "a plurality of duplicate mounting hr aokets adapted to encircle the connector sleeves andnest within said throat portion to lock the sleeve against axial movement, the said brackets being interchangeably adapted to encircle said tube sections loosely whereby the tube sections are free to float axially with respect to the connector sleeve.

. 5. An expansion joint for pneumatic tube systerns-comprising a connector sleeve, tube sec tions having their ends telescopically disposed within the opposite ends of the connector sleeve, the connector sleeve and tube sections respectively being of complementary oblong-cylindric shape in cross section, the cross section of the connector sleeve being substantially larger than the complementary tube cross section to provide annular spaces between the telescopically dis- 8 i posed sleeve and tube'sections, a plurality of sealing rings in said annular spaces formed from resilient material substantially circular in cross section, the said sealing rings being normally larger in diameter than the widthof the annular spaces to maintain the sealing rings under compression' radially in said annular spaces, the adjoining surfaces of the respective sleeve and tube sections within the annular spaces being substantially parallel axially whereby the said sealing rings are free to roll longitudinally in response to longitudinal shifting of the tubes relative to the sleeve, and weather seals secured to the opposite ends of the connector sleeve engaging the surface contour of the tube sections to enclose. andprotect the rolling seals.

EDWARD J. STOECKLIN.

REFERENCES CITED 7 The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

